It becomes active at night, seeking prey that is exhausted from the day's desert heat.

Y

Packs of them follow travellers through the desert until the travellers can no longer move.

Omega Ruby

During the daytime, Cacturne remains unmoving so that it does not lose any moisture to the harsh desert sun. This Pokémon becomes active at night when the temperature drops.

Alpha Sapphire

If a traveler is going through a desert in the thick of night, Cacturne will follow in a ragtag group. The Pokémon are biding their time, waiting for the traveler to tire and become incapable of moving.